Hi -

I tried to contact you earlier today to get advice on submitting multiple questions that are 'linked' to one overall question - no reply though.

Anyway, I would be be very grateful for your tutor's thoughts on the question[s] below please ? - there are actually seven questions, so please 'charge' me appropriately.

I'm about to submit an assignment but before I do would like expert opinion - which I've found your experts to be ! The question is...

Ganymede Assignment.

An astronomer is investigating the possibility of sending a satellite to Ganymede, a moon of Jupiter.

The plan is to use a rocket to launch the satellite into space above the Earth and then for the satellite to deploy a solar sail to carry it out to Ganymede. A solar sail is a large mirror which is pressed on by photons, particles of light, emitted by the sun thereby generating a small force.

The planned satellite would have a mass of 56.5 kg. When first deployed, the solar sail is expected to generate a propulsive force of 3.5 N.

Specific questions -

[1] What would be the initial acceleration of the satellite ?

[2] Assuming that the satellite starts from rest and the acceleration remains constant, how long would it take, in days, for the satellite to reach a speed of 100 km s^-1 ?

[3] How would you expect the force on the solar sail to change, (if at all), as the satellite moves away from the Sun and towards Ganymede ?

[4] It has been suggested to change the reflectivity of the mirrored surface of the sail so that it absorbs less light and reflects more light backwards. How would this affect the force generated by the solar sail ?

When the satellite reaches Ganymede, the plan is to send a small capsule down to the moon's surface.

[5] What is the difference between the capsule's mass and its weight ?

[6] On Earth, the capsule weighs 84 N. How much will the capsule weigh on Ganymede where the acceleration due to gravity is 1.428 m s^-2 ? - (with acceleration due to gravity on Earth taken to be 9.8 m s^-2)

[7] As the capsule descends to the surface of Ganymede, thrusters are used to provide an upward force. If the capsule descends at a constant velocity, how much upward force is provided by the thrusters ? - Ganymede has no atmosphere.

Very Many Thanks,

A